“This is so inconsequential as far as this campaign is concerned,” said Mrs. Bachmann, Minnesota Republican, on CNN’s “State of the Union.” “We have religious tolerance in this country, and we understand that people have different views on their faith.”

But while those Republican candidates clearly repudiated the idea that Mr. Romney’s Mormonism might be a concern to some voters, businessman Herman Cain, who along with Mr. Perry has emerged as the top threat to Mr. Romney’s front-runner status, was more vague, telling CNN he didn’t want to get into the matter.

“He is a Mormon, that much I know. I am not going to get into an analysis of Mormonism versus Christianity,” Mr. Cain said when asked whether Mr. Romney was a Christian. Asked to clarify his position, Mr. Cain said: “I am not running for theologian in chief.”

The former Godfather’s Pizza CEO, who is from Atlanta, predicted earlier this year that Mr. Romney’s Mormon religion would hurt him politically in the South.

“When he ran the first time, he did not do a good job of communicating his religion. It doesn’t bother me, but I know it is an issue with a lot of Southerners,” Mr. Cain said in a July 18 interview with The Washington Times.

Mr. Romney’s membership in the Church of Jesus Christ of Latter-day Saints, as the Mormon religion is formally called, erupted again as an issue in the Republican presidential contest Friday when the Rev. Robert Jeffress, a Dallas pastor, called the Mormon church “a cult” and said Mr. Romney is not a Christian.

Mr. Jeffress’ remarks came after he had introduced Mr. Perry at the Values Voters Summit, a Washington gathering of social conservatives — largely evangelicals and other Christians. Mr. Jeffress also called Mr. Romney a “good moral man” but said “those of us who are born-again followers of Christ should prefer a competent Christian.”

Mr. Perry and his staff immediately distanced the campaign from Mr. Jeffress, with Mr. Perry flatly rejecting the comments while stumping this weekend in Iowa.

In an interview with the Des Moines Register, Mr. Perry said: “I don’t think the Mormon Church is a cult. People who endorse me or people who work for me, I respect their endorsement and their work, but that doesn’t necessarily mean that I endorse all of their statements.”

Mr. Romney, who also spoke at the Values Voters Summit, indirectly addressed the issue of his religion, which dogged his unsuccessful 2008 campaign for the Republican nomination, by warning attendees against “poisonous language” directed at other religions.

Evangelicals, fundamentalists and other traditional-leaning Christians — traditionally important voting blocs for Republicans — widely consider the Mormon church not to be a Christian body. They claim it either denies or unrecognizably redefines such Christian doctrines as the Trinity, original sin, the atonement, the continuity of the church and the canon of Scripture.

Mr. Perry, who has made his own Christian beliefs a central element of his campaign, has not made an issue of Mr. Romney’s religion, but the Texas governor, who organized a “call to prayer” at Houston’s Reliant Stadium this summer that drew an estimated 30,000 people, has long-standing ties to the religious right.

Mr. Gingrich, in an appearance on CBS’ “Face the Nation,” called Mr. Jeffress’ comments “unwise and very inappropriate.” On “Fox News Sunday,” Mr. Santorum said dthat he doesn’t think Mormonism is a cult and that “every Mormon I know is a good and decent person.”